diff --git a/redis/connection/conn.go b/redis/connection/conn.go
index f7c12fe..023face 100644
--- a/redis/connection/conn.go
+++ b/redis/connection/conn.go
@@ -12,7 +12,7 @@ import (
 type Connection struct {
 	conn net.Conn
 
-	// waiting util reply finished
+	// waiting until reply finished
 	waitingReply wait.Wait
 
 	// lock while server sending response
@@ -50,7 +50,11 @@ func (c *Connection) Write(b []byte) error {
 		return nil
 	}
 	c.mu.Lock()
-	defer c.mu.Unlock()
+	c.waitingReply.Add(1)
+	defer func() {
+		c.waitingReply.Done()
+		c.mu.Unlock()
+	}()
 
 	_, err := c.conn.Write(b)
 	return err
diff --git a/redis/parser/parser.go b/redis/parser/parser.go
index 1c166cd..6c55b5b 100644
--- a/redis/parser/parser.go
+++ b/redis/parser/parser.go
@@ -39,16 +39,15 @@ func ParseOne(data []byte) (redis.Reply, error) {
 }
 
 type readState struct {
-	downloading       bool
+	readingMultiLine  bool
 	expectedArgsCount int
-	receivedCount     int
 	msgType           byte
 	args              [][]byte
-	fixedLen          int64
+	bulkLen           int64
 }
 
 func (s *readState) finished() bool {
-	return s.expectedArgsCount > 0 && s.receivedCount == s.expectedArgsCount
+	return s.expectedArgsCount > 0 && len(s.args) == s.expectedArgsCount
 }
 
 func parse0(reader io.Reader, ch chan<- *Payload) {
@@ -82,7 +81,7 @@ func parse0(reader io.Reader, ch chan<- *Payload) {
 		}
 
 		// parse line
-		if !state.downloading {
+		if !state.readingMultiLine {
 			// receive new response
 			if msg[0] == '*' {
 				// multi bulk reply
@@ -110,7 +109,7 @@ func parse0(reader io.Reader, ch chan<- *Payload) {
 					state = readState{} // reset state
 					continue
 				}
-				if state.fixedLen == -1 { // null bulk reply
+				if state.bulkLen == -1 { // null bulk reply
 					ch <- &Payload{
 						Data: &reply.NullBulkReply{},
 					}
@@ -129,7 +128,7 @@ func parse0(reader io.Reader, ch chan<- *Payload) {
 			}
 		} else {
 			// receive following bulk reply
-			err = readBulkBody(msg, &state)
+			err = readBody(msg, &state)
 			if err != nil {
 				ch <- &Payload{
 					Err: errors.New("protocol error: " + string(msg)),
@@ -158,7 +157,7 @@ func parse0(reader io.Reader, ch chan<- *Payload) {
 func readLine(bufReader *bufio.Reader, state *readState) ([]byte, bool, error) {
 	var msg []byte
 	var err error
-	if state.fixedLen == 0 { // read normal line
+	if state.bulkLen == 0 { // read normal line
 		msg, err = bufReader.ReadBytes('\n')
 		if err != nil {
 			return nil, true, err
@@ -167,7 +166,7 @@ func readLine(bufReader *bufio.Reader, state *readState) ([]byte, bool, error) {
 			return nil, false, errors.New("protocol error: " + string(msg))
 		}
 	} else { // read bulk line (binary safe)
-		msg = make([]byte, state.fixedLen+2)
+		msg = make([]byte, state.bulkLen+2)
 		_, err = io.ReadFull(bufReader, msg)
 		if err != nil {
 			return nil, true, err
@@ -177,7 +176,7 @@ func readLine(bufReader *bufio.Reader, state *readState) ([]byte, bool, error) {
 			msg[len(msg)-1] != '\n' {
 			return nil, false, errors.New("protocol error: " + string(msg))
 		}
-		state.fixedLen = 0
+		state.bulkLen = 0
 	}
 	return msg, false, nil
 }
@@ -195,10 +194,9 @@ func parseMultiBulkHeader(msg []byte, state *readState) error {
 	} else if expectedLine > 0 {
 		// first line of multi bulk reply
 		state.msgType = msg[0]
-		state.downloading = true
+		state.readingMultiLine = true
 		state.expectedArgsCount = int(expectedLine)
-		state.receivedCount = 0
-		state.args = make([][]byte, expectedLine)
+		state.args = make([][]byte, 0, expectedLine)
 		return nil
 	} else {
 		return errors.New("protocol error: " + string(msg))
@@ -207,18 +205,17 @@ func parseMultiBulkHeader(msg []byte, state *readState) error {
 
 func parseBulkHeader(msg []byte, state *readState) error {
 	var err error
-	state.fixedLen, err = strconv.ParseInt(string(msg[1:len(msg)-2]), 10, 64)
+	state.bulkLen, err = strconv.ParseInt(string(msg[1:len(msg)-2]), 10, 64)
 	if err != nil {
 		return errors.New("protocol error: " + string(msg))
 	}
-	if state.fixedLen == -1 { // null bulk
+	if state.bulkLen == -1 { // null bulk
 		return nil
-	} else if state.fixedLen > 0 {
+	} else if state.bulkLen > 0 {
 		state.msgType = msg[0]
-		state.downloading = true
+		state.readingMultiLine = true
 		state.expectedArgsCount = 1
-		state.receivedCount = 0
-		state.args = make([][]byte, 1)
+		state.args = make([][]byte, 0, 1)
 		return nil
 	} else {
 		return errors.New("protocol error: " + string(msg))
@@ -253,23 +250,21 @@ func parseSingleLineReply(msg []byte) (redis.Reply, error) {
 }
 
 // read the non-first lines of multi bulk reply or bulk reply
-func readBulkBody(msg []byte, state *readState) error {
+func readBody(msg []byte, state *readState) error {
 	line := msg[0 : len(msg)-2]
 	var err error
 	if line[0] == '$' {
 		// bulk reply
-		state.fixedLen, err = strconv.ParseInt(string(line[1:]), 10, 64)
+		state.bulkLen, err = strconv.ParseInt(string(line[1:]), 10, 64)
 		if err != nil {
 			return errors.New("protocol error: " + string(msg))
 		}
-		if state.fixedLen <= 0 { // null bulk in multi bulks
-			state.args[state.receivedCount] = []byte{}
-			state.receivedCount++
-			state.fixedLen = 0
+		if state.bulkLen <= 0 { // null bulk in multi bulks
+			state.args = append(state.args, []byte{})
+			state.bulkLen = 0
 		}
 	} else {
-		state.args[state.receivedCount] = line
-		state.receivedCount++
+		state.args = append(state.args, line)
 	}
 	return nil
 }
diff --git a/tcp/echo.go b/tcp/echo.go
index b2186a9..0314b66 100644
--- a/tcp/echo.go
+++ b/tcp/echo.go
@@ -44,13 +44,13 @@ func (c *EchoClient) Close() error {
 func (h *EchoHandler) Handle(ctx context.Context, conn net.Conn) {
 	if h.closing.Get() {
 		// closing handler refuse new connection
-		conn.Close()
+		_ = conn.Close()
 	}
 
 	client := &EchoClient{
 		Conn: conn,
 	}
-	h.activeConn.Store(client, 1)
+	h.activeConn.Store(client, struct{}{})
 
 	reader := bufio.NewReader(conn)
 	for {
@@ -69,7 +69,7 @@ func (h *EchoHandler) Handle(ctx context.Context, conn net.Conn) {
 		//logger.Info("sleeping")
 		//time.Sleep(10 * time.Second)
 		b := []byte(msg)
-		conn.Write(b)
+		_, _ = conn.Write(b)
 		client.Waiting.Done()
 	}
 }
@@ -78,10 +78,9 @@ func (h *EchoHandler) Handle(ctx context.Context, conn net.Conn) {
 func (h *EchoHandler) Close() error {
 	logger.Info("handler shutting down...")
 	h.closing.Set(true)
-	// TODO: concurrent wait
 	h.activeConn.Range(func(key interface{}, val interface{}) bool {
 		client := key.(*EchoClient)
-		client.Close()
+		_ = client.Close()
 		return true
 	})
 	return nil
diff --git a/tcp/server.go b/tcp/server.go
index 12f1b52..9a3d6cd 100644
--- a/tcp/server.go
+++ b/tcp/server.go
@@ -9,7 +9,6 @@ import (
 	"fmt"
 	"github.com/hdt3213/godis/interface/tcp"
 	"github.com/hdt3213/godis/lib/logger"
-	"github.com/hdt3213/godis/lib/sync/atomic"
 	"net"
 	"os"
 	"os/signal"
@@ -50,11 +49,9 @@ func ListenAndServeWithSignal(cfg *Config, handler tcp.Handler) error {
 // ListenAndServe binds port and handle requests, blocking until close
 func ListenAndServe(listener net.Listener, handler tcp.Handler, closeChan <-chan struct{}) {
 	// listen signal
-	var closing atomic.Boolean
 	go func() {
 		<-closeChan
 		logger.Info("shutting down...")
-		closing.Set(true)
 		_ = listener.Close() // listener.Accept() will return err immediately
 		_ = handler.Close()  // close connections
 	}()
@@ -70,13 +67,7 @@ func ListenAndServe(listener net.Listener, handler tcp.Handler, closeChan <-chan
 	for {
 		conn, err := listener.Accept()
 		if err != nil {
-			if closing.Get() {
-				logger.Info("waiting disconnect...")
-				waitDone.Wait()
-				return // handler will be closed by defer
-			}
-			logger.Error(fmt.Sprintf("accept err: %v", err))
-			continue
+			break
 		}
 		// handle
 		logger.Info("accept link")
@@ -88,4 +79,5 @@ func ListenAndServe(listener net.Listener, handler tcp.Handler, closeChan <-chan
 			handler.Handle(ctx, conn)
 		}()
 	}
+	waitDone.Wait()
 }